System and method for measuring animals

ABSTRACT

A system and method for measuring an animal includes a light source and an optical source. The light source, which is preferably an array of monochromatic light emitting diodes, at least partially backlights one or more of the animal&#39;s legs. The optical sensor or device, which is preferably a single dimension camera or charged-coupled device, opposes the light source and obtains an image that includes silhouettes of one or more legs of the animal. A processor, such as a computer with software and data storage, determines measurements, such as the approximate skeletal trunk length of the animal, from the silhouetted legs in the image. One or more first ultrasound transducers can be arranged to determine an approximate height of the pelvic region, and one or more second ultrasound transducers can be arranged to determine an approximate width of the pelvic region.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 10/619,921, filed Jul. 15, 2003 by John Conan DoyleII, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a system and method formeasuring growth of animals, such as cattle (beef and dairy), sheep,goats, and swine. More particularly, the present invention relates to asystem and method for measuring characteristics of an animal's skeletalstructure using optical and acoustic devices to determine the growthpotential of the animal.

BACKGROUND OF THE INVENTION

Various animals, such as beef cattle, dairy cattle, horses, sheep,goats, and swine, are raised for profit. For beef cattle, for example,it is preferred that the animal attains an optimum endpoint of tissuegrowth for it to be the most profitable. For a replacement dairy heifer,for example, it is preferred to minimize fat deposition in udder whilemaximizing bone, organ and muscle tissue. Increasing fat deposition inudder decreases heifers lifetime milking production potential. Whenconsidering the optimum endpoint of tissue growth and the optimum rateof growth, it is important to note that the weight at which animalsobtain the same chemical composition differs depending on the age, theskeletal size, the sex, or the maturity of the animals. Hence, chemicalcomposition of the animals can be different even when the weight of theanimals is the same. Based on their own visual prediction and days onfeed of the average meat quality grade or specification for the cattlein a pen, a feedlot manager may sell the entire pen of cattle at onetime, for example. As a consequence, a proportion of the beef cattle mayhave been overfed past optimal fat deposition, whereas some cattle havenot been fed to their genetic growth potential or maturity.

It is known in the art that English heifers are very easily overfedbecause they fatten readily at a light weight. However, Salers,Charolais, and other Continental breeds generally show their bestcarcass quality characteristics at much heavier weights than Englishbreeds. Thus, some of the cattle may not be marketed at their optimumeconomic tissue endpoint, taking into consideration live and carcassprices for the cattle, incremental cost of gain to feed the cattle, anddiscounts for under or oversized carcasses, insufficient, and excesscarcass fat on the cattle.

Work done by Dr. John Brethour (The Composition of Growth in Beef Cattlein Honor of Dr. Rodney L. Preston,” Texas Tech University, Lubbock, Aug.2, 1996) and studies completed at Kansas State University indicated thatthe economic consequences of suboptimal marketing of fed cattleinclude: 1) costs of %1/head/day for each day away from optimalmarketing date that an animal is under or over fed (greater than 30% ofthe pen is marketed more than 25 days away from their optimal marketingdate); and 2) results in $3.50 per hundred weight (cwt) increased costof gain throughout the feeding period when marketing cattle greater than28 days beyond the optimum. However, when cattle are sorted three ways,less than 3% of the cattle in a pen are marketed greater than 20 daysfrom their optimum tissue endpoint. Thus, identifying reliable andeffective techniques for optimum economic tissue endpoint will improveend-product quality and consistency and will positively impactprofitability of fed cattle.

Currently, optimum endpoints of growth in feedlot animals can beachieved by predicting such things as the incremental cost of gain, thecarcass quality, and the yield grade. Equations to predict incrementalcost of gain and accounting for differences in net energy formaintenance requirements (NE_(m)) of the animals, the effect ofenvironment on maintenance requirements (NE_(m)), the differences inbody size, the implant program and feeding system have been reported inthe Journal of Animal Science, Volume 70 by Sniffen et al. (1992; page3562 to 3577) and Fox et al. (1992; page 3578 to 3596) and in the 1996NRC model (currently known as the Cornell Net Carbohydrate and ProteinSystem). Equations to predict carcass weight and body composition ofdifferent beef cattle breeds finished at three different endpoints havealso been reported in the Journal of Animal Science, Volume 69, page4696 to 4702, by Perry et al. (1991), in the Journal of Animal Science,Volume 72, page 1806 to 1813 by Tylutki et al. (1994), and in thejournal of Animal Science, Volume 75, page 300 to 307 Perry and Fox(1997).

In addition, several reports and technologies exist in the art thataddress the issues of growth and management, particularly in feedlotcattle. For example, U.S. Pat. Nos. 4,733,971; 4,889,433; 4,815,042;5,340,211; and 5,315,505 to Pratt pertain to the delivery of feedadditives and inventory of drugs for feedlot cattle. U.S. Pat. No.5,673,647, U.S. patent application Ser. No. 08/838,768, and U.S. PatentApplication Publication No. 20020050248 disclose automated systems formanaging and monitoring cattle. Ultrasound techniques have beendeveloped to measure backfat in cattle by Professor John Brethour asexplained in an article entitled “Use of Ultrasound to Estimate BodyComposition” presented at a symposium entitled, “The Composition ofGrowth in Beef cattle in Honor Of Dr. Rodney L. Preston,” Texas TechUniversity, Lubbock, Aug. 2, 1996.

In the art of managing cattle, body weight is commonly used to projectfeed performance or to estimate economic profitability of the cattle.Techniques for weighing cattle are disclosed in the following U.S. Pat.Nos. 4,288,856; 4,617,876; and 4,280,448. The measurement of animalweight is used because the measuring equipment is relatively simple.However, animal weight is highly variable and thus, represents a poorindicator of animal growth. For example, body weight is sensitive to thevolume of water (tissue and gastrointestinal tract content). Measurementof body water and specific gravity are indirect methods of estimatingbody composition, as reported in the Journal of Biological Chemistry,Volume 158, page 685 to 696 by Pace and Rathbun (1945). Using body waterand nitrogen measurements of guinea pigs, the authors concluded that thewater content of the lean body mass is 73% and thus should be areasonable estimate of most species of mammals (Pace and Rathbun, 1945).The drive to measure body water generated the use of various proposeddilution techniques involving deuterium, tritium, antipyrine, and urea.The decrease in body weight due to water loss is termed “shrink” and iswell recognized in the beef industry.

Not only is the amount of weight loss an animal experiences dependentupon recent water intake, but also it is dependent upon other factors,such as feed intake and stresses related to transport or sickness.Furthermore, cattle are fed differently around the world so that thepercentage of empty body weight due to fat deposits (empty body weightfat percentage is sometimes referred to as empty body weight fat) andthe maturity of the animals can vary dramatically from place to place.As an example, cattle of similar age, sex, breed, and weight are fedeither low or high-energy ration. These cattle will both grow similarskeletal, organ, and muscle deposits. However, the cattle fed low energyration will possess lower empty body weight fat percentage, whereascattle fed the high energy ration will possess higher levels of emptybody weight fat, have heavier weights because of additional fat, andhave an eventual higher carcass dressing percentage.

Skeletal measurements of the cattle can avoid some of the transientfactors associated with merely measuring the weight of the animalsdiscussed above because changes in an animal's skeleton are independentof feed and/or water intake and transient environmental stress. As ananimal grows and metabolizes nutrients, tissues are deposited throughthe following sequential series from first to last: nervous system, bonetissue, organ tissue, muscle tissue, and fat. In addition, tissues aredeposited from the cranial to caudal region of the animal from first tolast: head, neck, thorax, rump, loin, and rib area. Bone tissues thatare deposited as skeletal structure regulate muscle deposition, redblood cell production, and various immunological factors and can,therefore, be a suitable determining factor of an animal's growthpotential. Furthermore, skeletal measurements are not influenced bywater loss or adequacy and are, therefore, a more adequate method todefine the body size of the animal. In addition, the author's ownresearch has shown that skeletal pelvic height has a high correlation tofinished carcass weight for the animal compared to entry and finishedweights for cattle fed over a 70-day period.

Physical measurements including pelvic measurement can be used toestimate animal characteristic, such as potential skeletal and muscledevelopment. Typical parameters used in such estimates are hip heightand width, shoulder width, and body length. Measurements of theseparameters can be used to calculate shoulder muscle to bone ratio, rumpmuscle to bone ratio, and musculoskeletal development per unit heightand length. It is believed that skeletal size or hip height of cattlecan be correlated with the ultimate carcass weight of the cattle fed fora 70-day period. It is also believed that the shoulder height and thebody length of cattle can be used to determine the potential averagedaily gain and feed conversion to final body weight of the cattle.

Unfortunately, making manual measurements of the cattle's shoulderheight and body length are time consuming and less reliable. Moreover,determining points on the cattle for making such manual measurements arenot well defined on the 3-dimensional animals. It is known in the art touse a conventional 2-dimensional video camera to obtain an image of theanimal. The image taken with the 2-dimensional video camera, however, isnot particularly useful for determining the skeletal trunk size of theanimal. The image includes body mass from muscle and fat and can beconfounded by lighting conditions and the hide color of the animal, forexample, making it difficult to differentiate the body tissuecomposition (bone, muscle & fat) of the animal. For example, theanatomical juncture of the neck with the shoulder (i.e., major tubercleof humers or “point of shoulder”) is not well defined in such an imagemade with a 2-dimensional video camera because muscles in thisanatomical region of the neck make it difficult to distinguish theskeletal elements of the major tubercle of humerus.

Another method of measuring animals uses ultrasound technology. Suitableteachings of measuring animals with the ultrasound technology aredisclosed in WO99/67631, AU744213, AU449219, and CA2335845, which areincorporated herein by reference in its entirety. The reader is alsoreferred to the following references that describe techniques formeasuring animals: U.S. Pat. Nos. 4,745,472; 5,483,441 and 5,576,949, CA2216309; and JP 10206549.

Although the techniques discussed above are useful, feedlot managers oroperators are constantly seeking to improve measurement and managementtechniques for animals. Accordingly, a need exists in the art foraccurate techniques to measure the skeletal structure of animals thatcan enhance a feedlot manager's ability to manage the animals to anoptimum economic endpoint, thus avoiding discounts for too much fat andoutsized carcasses and avoiding the economic consequence of suboptimalmarketing of cattle (e.g., increased cost of gain).

The present invention is directed to overcoming, or at least reducingthe effects of, one or more of the problems set forth above.

SUMMARY OF THE PRESENT DISCLOSURE

A system and method for measuring an animal includes a light source andan optical sensor or device. The light source and optical sensor arearranged to oppose one another and can be mounted in sidewalls of ameasurement unit. The light source backlights a portion of the animal'slegs. In one embodiment, the light source is a plurality of lightemitting diodes arranged in an array. The optical sensor obtains animage that includes silhouettes of the portion of the animal's legs. Inone embodiment, the optical sensor is a charged-coupled-device or asingle dimension video camera. A processor, such as a computer withsoftware and data storage, can analyze the silhouetted legs on the imageto determine the skeletal trunk length of the animal. One or more firstultrasound transducers can be arranged to determine an approximateheight of the animal's pelvic region. In addition, one or more secondultrasound transducers can be arranged to determine an approximate widthof the animal's pelvic region. The disclosed system and method can beused to identify differences in skeletal changes of animals throughrepeated measurements over the life of the animals. Animals can beindividually identified early in life and can then be monitored forchanges in skeletal growth over various time periods throughout theirlives.

The foregoing summary is not intended to summarize each potentialembodiment or every aspect of the invention disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, preferred embodiments, and other aspects of thesubject matter of the present disclosure will be best understood withreference to a detailed description, which follows, when read inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a plan view of an animal disclosed system accordingto certain teachings of the present disclosure.

FIG. 2A illustrates a detailed plan view of the disclosed system of FIG.1.

FIG. 2B illustrates an end view of the disclosed system, showing theimaging system and one arrangement of the acoustic devices.

FIG. 3A illustrates a plan view of the disclosed system, showing anotherarrangement of the acoustic devices.

FIG. 3B illustrates a plan view of the disclosed system, showing anotherarrangement of the optical sensors.

FIG. 4A illustrates skeletal structure of cattle.

FIG. 4B illustrates the correlation between the measurements from thedisclosed system and the dimensions of cattle.

FIG. 5 diagrammatically illustrates measurements taken with thedisclosed system according to certain teachings of the presentdisclosure.

While the disclosed system and method are susceptible to variousmodifications and alternative forms, specific embodiments and inventiveconcepts of the disclosed system and method have been shown by way ofexample in the drawings and are herein described in detail. The figuresand written description are not intended to limit the scope of thedisclosed inventive concepts in any manner. Rather, the figures andwritten description are provided to illustrate the disclosed inventiveconcepts to any person skilled in the art by reference to particularembodiments, as required by 35 U.S.C. § 112.

DETAILED DESCRIPTION

Referring to FIG. 1, an embodiment of an animal disclosed system 10 formaking a number of measurements of animals, such as cattle, isschematically illustrated in a plan view. The disclosed system 10 can beused in conjunction with common devices for directing and sortinganimals, such as an alleyway 20, squeeze chute 22, and sorting pens 24.The disclosed system 10 is constructed to allow a single animal A toenter, stand, and exit the disclosed system 10 at one time. In oneembodiment, for example, the disclosed system 10 has a rectangularframework with sidewalls 12 and 14 of approximately 2.5-m long and 2.0-mhigh. An entry point or posterior door 16 and an exit point or anteriordoor 18 are attached to the sidewalls 12 and 14 to control the entry andexit of the animal A. The anterior dorsal aspect of the disclosed system10 can be fitted with an adjustable flap 30 to block anterioradvancement of a smaller animal and to keep the caudal region of theanimal near the posterior door 16. Alternatively, the unit can haveother devices to position the animal in the unit that use light, sound,hydraulics, or compressed air, for example. Because the disclosed system10 is used in the handling, sorting, and confinement of animals, it ispreferably constructed using the common techniques known in the art forsuch structures.

To allow the animal to enter, the posterior door 16 is opened manuallyor automatically. As the animal enters or stands in the disclosed system10, the identity of the animal can be assigned by management, determinedvisually or electronically using methods known in the art. Theinformation can include the animal's lot or identification number, age,sex, breed, market classification, domestic information relating togrowth hormones, frame score, and any other pertinent informationrelating to the animal. For example, an ear tag on the animal may havean identification number, which can be input manually by an operator. Inaddition, the disclosed system 10 of the present disclosure can be usedwith existing systems for managing feedlot animals, such as computersystems known in the art that can automatically identify individualanimals for handling and sorting. Information of the animal can bedetected by an entry device 32 and automatically input into theprocessing system 80. For example, the entry device 32 can performinfrared analysis of a bar coded tag on the animal. The entry device 32can also be programmed to record signals from internal or externaltransponders on the animal. Such transponders for identifying animalsare known in the art. Preferably, information, such as age, sex, breed,and the like are stored in the processing system 80 so that there is noneed for these values to be re-entered when the animal is re-measured.

After the animal enters, the posterior door 16 is shut, and theadjustable flap 30 is moved to keep the caudal region of the animal nearthe posterior door 16. The flap 30 can be controlled by an operator orcan be operated automatically. While the animal is in the disclosedsystem 10, a number of devices make external measurements of the animalfor later determination of the animal's skeletal structure, which aredescribed below. The disclosed system 10 can have a scale (not shown) inthe floor or can be adapted for use with an existing weight scale.Alternatively, the weight of the animal can be determined at a differentsite and the information recorded or input into the processing system80, as desired.

The disclosed system 10 also includes a sensing system 40 and an imagingsystem 70. The sensing system 40 is used for measuring the pelvic heightH_(P) and pelvic width W_(P) of the animal and preferably includes aplurality of ultrasound transducers 50, 60, and 62 detailed in FIG. 2A.In addition to measuring the pelvic height Hp of the animal, the sensingsystem 40 could similarly measure the height and/or width of the animalat the shoulder as well. The imaging system 70 is used for measuring theskeletal trunk length L of the animal and preferably includes a lightsource 72, an optical device or sensor 74, and an image processor 76. Asdescribed in more detail below, the sensing system 40 and the imagingsystem 70 of disclosed system 10 externally and non-invasively obtainskeletal measurements of the animal without restraining the animal ormaking physical contact with the animal. Depending on a particularimplementation and facility, the various measuring devices of thesensing system 40 and the imaging system 70 can be activated manually byan operator. Alternatively, the various measuring devices can beautomatically triggered by the posterior door 16 opening, by theapplication of weight on the scale, or by activation of an infraredsensor or motion detector, for example.

When measurements have been obtained with the scale, the sensing system40, and the imaging system 70, the processing system 80 has thedifferent data from the individual devices (e.g., electronicidentification from the entry device 32, distances from the ultrasoundtransducers 50 and 60, 62, the image from the imaging system 70, weightfrom the scale, etc.). The animal is then allowed to exit the disclosedsystem 10. The adjustable flap 30 is moved, and the anterior door 18 isopened either manually or automatically. An exit device 34 can mark orotherwise tag each animal with an identifier as it exits the disclosedsystem 10. For example, the exit device 34 can mark the exiting animalswith different color paints for visual identification. In anotherexample, the exit device 34 can add electronic information to electronicear tags on the animals, can add visual information to non-electronicear tags on the animals, or can provide other identifiers by whichindividual animals can be identified later. Such identification devicesfor tagging or marking animals are known in the art and can be used forlater managing, feeding, and sorting the individual animals. Topicalinsecticides and anti-parasite drugs can also be administered fromdevices as the animal exits the disclosed system 10.

Once the animal exits the disclosed system 10, the animal can then enterthe squeeze chute 22 (e.g. to apply identification on the animal whenrequired) and can be positioned to move forward to animal drafting andsorting pens 24. When animals are being processed for the first time,they may not have any identification when entering the unit formeasurements. In such a case, first measurements can be initiallyobtained with the unit and can be stored in the processing system 80.Once identification, such as an electronic ID, bar coded ear tag, ornumbered ear tag, is administered or attached to the animal, they can begenerally sorted into pens. The second time these animals enter theunit, which could be about 70 days later, for example, they will havetheir identification and will be measured a second time for furtherevaluation. For example, the difference in the first and secondmeasurements (i.e., weight, skeletal length, pelvic height, and pelvicwidth) can be used to determine and assign a specific implant treatmentand/or feeding program. Consequently, selection of particular sortingpens for the exiting animals based on the measurements obtained with thedisclosed system 10 can be used to place individual animals withparticular, measured characteristic and known information in a sortingpen having animals with similar characteristics. Sorting the animals inthis way can enable a feedlot manager to apply various regimens of feed,growth promotants, and the like to particular animals or groups ofanimals, depending on their age, breed, sex, skeletal structure, etc.The animals sorted into various groups can be fed the same rations sothat they efficiently and effectively obtain substantially the sametissue composition.

Referring to FIG. 2A-B, more detailed plan and end views of thedisclosed system 10 of FIG. 1 are illustrated, showing an animal Awithin the disclosed system 10. As alluded to above, the sensing system40 and the imaging system 70 make external measurements of the animalfor later determination of the animal's skeletal structure size orcoefficients. A processing system 80 is coupled to the sensing system 40and the imaging system 70 and processes data from these systems 40 and70. The processing system 80 can also be coupled to the other componentsof the disclosed system 10, including the entry device 32 and exitdevice 34, for example. In one embodiment, the processing system 80 caninclude a computer having appropriate software and data storage. In analternative embodiment, the processing system 80 can be controlled by amanager through an office communication or a computer link. In otherwords, decision on how to draft, manage, or administer to the animalscan be made by remote office decisions that set particular parameters.

The sensing system 40 preferably includes one or more acoustic devices50 and 60, 62 for measuring distances to the pelvic region of the animalA. As described in more detail below and as best shown in FIG. 2B, thedistances measured with the acoustic devices 50 and 60, 62 are then usedto determine the approximate pelvic height H_(P) and pelvic width W_(P)of the animal. The imaging system 70 preferably includes a light source72, an optical sensor 74, and an image processor 76 for determining theposition of the animal's legs h_(L), h_(R), f_(L), and f_(R). Asdescribed in more detail below and as best shown in FIG. 2A, thepositions of the animal's legs h_(L), h_(R), f_(L), and f_(R) are thenused to determine the approximate skeletal trunk length L of the animal.

As best shown in the end view of FIG. 2B, the light source 72 isinstalled near the bottom of the first sidewall 12. The light source 72can be a linear array of lights, such as an array of monochromatic lightemitting diodes (LEDs) with diffusers. The optical sensor 74 is opposedto the light source 72 and is installed in the second sidewall 14. Theoptical sensor 74 is preferably a single dimension video camera orlinear charged-coupled-device. Preferably, the light source 72 andoptical sensor 74 are arranged to view the legs of the animal A in thelocation of the metacarpus (not shown in FIG. 2B) on the forelegs andthe metatarsus M_(T) of the hind legs h_(L-R) of the animal. A lens 75can be used to limit the vertical field of view of the optical sensor74. In the opposing arrangement of the present embodiment, the lightsource 72 backlights the legs of the animal so that the optical sensor74 can capture a well-defined, contrasted image of the position of thelegs. Although not preferred, the light source 72 may be arranged toilluminate the legs from the same side of the disclosed system as theoptical sensor 74, and the image processor 76 coupled to the opticalsensor 74 may include filters to improve the definition and contrast ofthe captured image.

As best shown in the plan view of FIG. 2A, the light source 72 andoptical sensor 74 are preferably arranged to view the legs of the animalin a field of vision θ ranging from about 45° to 60°. To allow theoptical sensor 74 to view a substantial portion of the bottom length ofthe disclosed system 10, the optical sensor 74 can be positionedlaterally away from the sidewall 14 of the disclosed system 10. Althoughthe optical sensor 74 is preferably a single dimension video camera orlinear charged-coupled-device; a photodiode array, a CMOS opticalsensor, a still photographic camera, a digital camera, a conventional2-dimension camera, or other image device can be used as long as thesame information of the positions of the animal's legs detailed belowcan be obtained as with the preferred single dimension video camera orlinear charged-coupled-device. Use of a conventional 2-dimension camera,for example, may require processing and truncating of the image toproduce an image comparable to a single dimension video camera or linearcharged-coupled-device.

In an alternative arrangement to the embodiment of FIG. 2A-B, thedisclosed system 10 as embodied in FIG. 3B can include first and secondlight sources 72 _(f) and 72 _(h) respectively positioned in the firstsidewall 12 at the general locations of the forelegs f_(R-L) and hindlegs h_(R-L) of the animal A. In addition, the disclosed system 10 asembodied in FIG. 3B can include first and second optical sensors 74 _(f)and 74 _(h) opposing these dual light sources 72 _(f) and 72 _(h). Theteachings disclosed herein for the embodiment of FIGS. 2A-B can bereadily applied to this alternative arrangement of dual light sources 72_(f) and 72 _(h) and optical sensors 74 _(f) and 74 _(h) illustrated inFIG. 3B.

Returning to the embodiment of FIGS. 2A-B, the imaging system 70monitors the leg movement and position of the legs h_(L), h_(R), f_(L),and f_(R), as the animal enters and stands in the disclosed system 10.The output signals from the optical sensor 74 are sent to the imageprocessor 76, which can include optical train and background filters,among other components known in the art of image processing. Thepositions of animal's legs are accepted or rejected based on clarity,resolution, and other factors. A light signal, audio signal, visualdisplay, or other like indicator, for example, can provide an operatorof the disclosed system 10 with an indication that the imaging system 70has successfully captured a measurable image of the animal's legs h_(L),h_(R), f_(L), and f_(R). The data from the imaging system 76 is thensent to the processing system 80 for analysis. As noted above, theprocessing system 80 can be a computer having software and, therefore,can include components and software for the image processor 76 as well.

While the animal is in the disclosed system 10, the acoustic devices 50and 60, 62 measure distances to the pelvic region of the animal. Asalluded to above, the sensing system 40 could include acoustic devicesto measure the height and/or width of the animal at the shoulder, ifdesired. For example, one or more acoustic devices could be arranged ormoved near the shoulder region of the animal for measuring distances tothe shoulder region and obtaining shoulder measurements in a similarfashion to that disclosed herein for obtaining pelvic measurements.Activation of the acoustic devices 50 and 60, 62 can be done manually byan operator. For example, an operator can observe that the animal is inplace and that the imaging system 70 has captured a measurable image.Then, the operator can manually activate the acoustic devices 50 and 60,62. Alternatively, activation of the acoustic devices 50 and 60, 62 canbe done automatically. For example, the processing system 80 canautomatically activate the acoustic devices 50 and 60, 62 when ameasurable image is captured with the imaging system 70. Alternatively,the disclosed system 10 can include an infrared detector or other devicethat can detect when an animal is in a certain position within thedisclosed system 10.

The acoustic device 50 is preferably used to measure the verticaldistance to the top of the pelvis, because this is typically the tallestpart of the animal's body. The other acoustic devices 60, 62 arepreferably used to measure lateral distances to the pelvic region. Thedistances measured with the acoustic devices 50 and 60, 62 are then usedto determine the approximate pelvic height H_(P) and width W_(P) of theanimal. The acoustic devices 50 and 60, 62 preferably include ultrasoundtransducers known in the art. Suitable teachings for using ultrasoundtransducers and measuring distances to animals are disclosed in WO99/67631 (now issued as U.S. Pat. No. 6,591,221), which is incorporatedherein by reference in its entirety.

To measure a vertical extent of the pelvic region on the animal andultimately obtain the approximate pelvic height Hp, the ultrasoundtransducer 50 is positioned dorsally above the animal near the posteriordoor 16. In the embodiment of the disclosed system 10 shown in FIG. 2A,only on ultrasound transducer 50 has a fixed location in the disclosedsystem 10 and can be able to detect reflected ultrasound signals fromthe pelvic region of the animal under most circumstances. As detailedbelow and as best shown in FIG. 2B, the pelvic height H_(P) of theanimal is calculated by the difference between the distance between theultrasound transducer 50 and the animal and the known distance betweenthe ultrasound transducer 50 and the floor of the disclosed system 10.

As is known, a typical ultrasound transducer generates, amplifies, andtransmits a signal, which is reflected from the animal and returns tothe transducer. The signal is received, amplified, and processed toprovide information as to the distance of a location on the animal'ssurface to the transducer. For the disclosed system 10, the output forthe ultrasound transducer 50 preferably directs a 1-ms tone burst,producing a sound pressure level at about 50 k-Hz of approximately118-dB SPL at 1 meter. Typically, the distance between the animal andthe ultrasound transducer 50 may then be measured within 1 to 2 secondsor less.

The ultrasound transducer 50 is located above the animal so as to directan ultrasonic signal towards the dorsal section of the animal's pelvicregion. When the pelvic height H_(P) is being measured, the animal ispreferably measured in a freestanding position. Because the animal isallowed to stand freely within the disclosed system 10, the relativevertical location of the ultrasound transducer 50 relative to the pelvismay vary along the length of the animal. However, the ultrasoundtransducer 50 preferably generates ultrasonic signals that are conicalin shape and are incident in a circular manner on the animal. Theultrasonic signals generated by the ultrasound transducer 50 can have adiameter of between about 20-cm and about 60-cm. Preferably, theultrasonic signals generated by the ultrasound transducer 50 has adiameter between 35-cm and 50-cm and more preferably about 40-cm.

It is believed that with these conditions at least some of the generatedsignal will reflect from the desired location of the pelvis under mostcircumstances. In addition, it is preferred that the processing system80 is able to calculate the distance between the ultrasound transducer50 and the highest point on the animal that reflects a signal. Thus, itmay not be necessary for the animal to be precisely positioned such thatthe pelvis is directly aligned with the ultrasound transducer 50.Animals having lengths within a certain range, therefore, can bemeasured with the single ultrasound transducer 50 being located in thesame position. The range of lengths of the animals that can be measuredin this way may depend on the diameter of the ultrasonic signal and theangle at which the signal is directed towards the animal. To measureanimals outside a particular range, ultrasound transducer 50 may bemounted to a track or guide to enable it to be moved along the length ofthe animal to the desired pelvic region. As best shown in FIG. 2B, forexample, the ultrasound transducer 50 can be mounted on a rack 36 withrollers 38 or the like. Thus, the ultrasound transducer 50 can be ableautomatically or manually moved relative to the pelvic region of theanimal to make the vertical measurement. A motor and a drive or an airram (not shown) can also be used to automatically move the rail 36 andthe ultrasound transducer 50. The ability to adjust the position of theultrasound transducer 50 can be desirable if the ultrasound transducer50 is intended to measure animals of various size differences, forexample. In an alternative embodiment shown in FIG. 3A, a plurality ofultrasound transducer 50 can be fixedly mounted in the disclosed system10 for making vertical measurements at various points along the lengthof the disclosed system 10.

To measure a lateral extent of the pelvic region on the animal andultimately obtain the approximate pelvic width W_(P), a pair of acousticdevices 60, 62, preferably ultrasound transducers, are positionedlaterally on both sides of the animal's pelvic region near the posteriordoor 16. In the embodiment shown in FIG. 2A, the pair of opposingultrasound transducers 60, 62 can be fixedly mounted in the disclosedsystem 10 and capable of measuring distances to the animals pelvicregion in a manner similar to that described above. As shown in FIG. 2B,the pair of opposing ultrasound transducers 60, 62 can alternatively bemounted on the rail 36 having wheels 38 so that the ultrasoundtransducers 60, 62 can be automatically or manually moved relative topelvic region of the animal to make lateral measurements. In yet anotheralternative shown in FIG. 3A, a plurality of opposing ultrasoundtransducers 60, 62 can be fixedly mounted in the disclosed system 10 formaking lateral measurement. In these arrangements, the lateralultrasound transducers 60, 62 are preferably positioned in verticalalignment with the vertical acoustic device 50 so that they measuresubstantially the same area of the pelvic region of the animal.

Because the disclosed system 10 includes two or more ultrasoundtransducers 50 and 60, 62, it is preferred that the signals from therespective transducers do not interfere with each other. This may beachieved by programming the transducers 50 and 60, 62, to generateultrasonic signals in an alternating manner. Alternatively, themeasurements can be made separately and sequentially. This can beconducted by either measuring the animal sequentially as it stands in asingle location or by measuring one dimension with one transducer (e.g.,50) in a first position and then moving the animal to a second positionfor a second measurement to be taken with other transducers (e.g., 60and 62). Of course, conducting the measurements in this manner wouldrequire the disclosed system 10 to be longer than shown in the Figures.

Referring to FIGS. 4A-B, aspects of the skeletal structure of cattle andthe measurements made with the disclosed system 10 are illustrated. InFIG. 4A, some of the skeletal structure of a cow is shown by way ofexample and is not intended to limit the sex or age of the cattle. InFIG. 4B, the correlation between the measurements obtained with thedisclosed system 10 of FIGS. 1-3B and the dimensions of the cow'sskeletal structure are schematically shown. As best shown in FIG. 4A,the cranial skeletal trunk aspect (front) of the animal is defined bythe major tubercle of the humerus or “point of shoulder” PS. The caudalaspect (rear) of the animal, such as the pelvic ischiatic tuber or tailposterior, is a less well-defined anatomical point on cattle. Muscle,fat, and the extension of the tail in the caudal aspect can distortmeasurement in the rump or pelvic area. The disclosed system provides anaccurate assessment of animal skeletal trunk length L or center ofgravity when the animal is in a natural stance or is in motion (e.g.,walking or stepping).

As best shown in FIG. 4B, the cow's natural center of gravity for theforeleg pair f_(L-R) lies approximately at the mid-point distancebetween forelegs f_(L-R). This midpoint is substantially perpendicularto the point of shoulders PS of the animal. The cow's natural center ofgravity for the hind leg pair h_(L-R) lies approximately at themid-point distance between hind legs h_(L-R). This hind midpoint is alsosubstantially perpendicular to major trochanters of the femurs (hipjoints) HJ on the pelvic region of the animal. Therefore, an approximateskeletal trunk length L for the cow can be obtained by determining thedistances between midpoints of the foreleg pair f_(L-R) and the hind legpair h_(L-R). Measuring the position and distances between the legsh_(L-R) and f_(L-R) of the animal is readily repeatable. Furthermore,the legs h_(L-R) and f_(L-R) are not disguised by muscle, fat, and otherexternal features of the animal, making optical measurement reliable.

Referring to FIG. 5, the measurement process that occurs in thedisclosed system 10 briefly described above is diagrammatically shown.With the animal in the disclosed system 10, the imaging system 70 havingthe opposing light source 72 and the optical sensor (not shown) is usedto produce an image 90 of the lower portion of the animal's legs h_(L),h_(R), f_(L), and f_(R). Because the linear monochromatic light source72 is located opposite the optical sensor (not shown), the light source72 backlights the position of the animal's legs h_(L), h_(R), f_(L), andf_(R). The resulting image 90 has silhouettes 92, 94, 96, and 98 of theindividual legs h_(L), h_(R), f_(L), and f_(R) of the animal A.Preferably, the light source 72 and optical sensor are positioned at alevel to produce an image of the region of the cattle's legs h_(L),h_(R), f_(L), and f_(R) having the metacarpus and metatarsus bones, bestshown in FIG. 4A.

The average separations or midpoints between the legs in each pair ofsilhouettes 92, 94 and 96, 98 are used to identify cranial and caudalextent (skeletal trunk length L) of the animal. On animals and moreparticularly on cattle, the midpoint M_(F) between the fore leg pairf_(L-R) is substantially perpendicular to the cranial skeleton region(i.e., major tubercle of humerus or point of shoulder PS of FIGS. 4A-B).In addition, the midpoint M_(h) between the hind leg pair h_(L-R) issubstantially perpendicular to the caudal skeleton region (i.e., themajor trochanter of femur or hip joints HJ in FIGS. 4A-B). The distancebetween these midpoints M_(H) and M_(F) is proportionate to theapproximate skeletal trunk length L of the animal (i.e., the distance Lbest shown in FIG. 4B from the major trochanter of femur PS to the majortubercle of humerus HJ). It is believed that almost any combination ofpositions of the leg pairs h_(L-R) and f_(L-R) may be used to identifythe skeletal trunk length L of the animal's body or the center ofgravity defining the skeletal trunk size. In addition to determiningskeletal trunk length L, the width of one or more single leg silhouettes(e.g., 92) corresponding to the metacarpus and metatarsus of the legsmay be further used as a separate measurement to indicate bone diameter.

The disclosed system determines a scaled skeletal trunk length l of theanimal from the recorded image 90. The disclosed system first calculatesa relative distance d_(H) between the hind leg pair h_(L) and h_(R), andcalculates a relative distance d_(F) between the fore leg pair f_(L) andf_(R) from the image 90. The image 90 may be or may be converted to adigital image, for example, composed of a plurality of pixels. The pixelsize of the image 90 and the relative number of pixels per square inchor length may be known, for example. Thus, the disclosed system candetermine distances by computer iterations that count separation betweenor widths of the silhouettes based on changes in contrast betweenindividual pixel values to determine the relative distances d_(H) andd_(F). These and other techniques for processing images are known in theart. The relative distances d_(H) and d_(F) can then be divided todetermine their midpoints M_(H) and M_(F). The separation between themidpoints M_(H) and M_(F) can then be calculated.

The separation between the midpoints M_(H) and M_(F) represents thescaled skeletal length l of the animal. To calculate an approximateskeletal length L of the animal using the scaled length l, the knownangular view θ of the optical sensor 74, the scaled length l, and theknown or average distance D of the optical sensor 74 from the animal Aare used,

where: $L \cong {l + {2D\quad{{\tan( \frac{\theta}{2} )}.}}}$

This formula is based on geometrical calculation. However, determiningthe skeletal length L of the animal using the scaled length can beperformed using a scale factor derived experimentally. For example, thewidth of the opposing light source 72 is known as well as the distancebetween the light source 72 and the optical sensor 74. Using these knownvalues, the scale of the image 90 can be determined empirically.

With the location of the hind legs h_(L) and h_(R) identified, thedisclose system activates the vertical and lateral ultrasoundtransducers 50 and 60, 62. When activated, the ultrasound transducers 50and 60, 62 obtain distances from the individual devices 50 and 60, 62 tothe body of the animal. In the present arrangement, the two lateralultrasound transducers 60, 62 are simultaneously activated to obtain ameasurement of the pelvic width W_(P) of the animal. The verticalultrasound transducer 50 is activated to obtain a measurement of thepelvic height H_(P) of the animal. These measurements are sent to thesoftware program in the processing system for interpretation.

The lateral ultrasound transducers 60, 62 each implement an ultrasonicwave, which is reflected when encountering the animal A. The ultrasoundtransducers 60, 62 receive the reflected signal. The speed of the soundwaves is then divided by the travel times between the transmission andreception of the ultrasonic signals in order to approximate therespective distances d₁ and d₂ from the ultrasound transducers 60, 62 tothe animal. Knowing the separation d₃ between the lateral ultrasoundtransducers 60, 62, the approximate pelvic width WP of the animal can beobtained,

where:W _(P) ≅d _(3(BetweenTransducers60,62))−(d ₁ +d ₂).

In a similar fashion, the approximate pelvic height H_(P) of the animalis calculated using the known height H of the vertical ultrasoundtransducer 50 and the measured distance d₄ that the transducer 50 isfrom the pelvic region of the animal,

where:H _(P) =H _((Transducer50)) −d ₄.

After the above calculations are performed, the disclosed system 80 inFIGS. 1-2B has the approximate weight W_(kg), pelvic height H_(P),pelvic width W_(P), and skeletal trunk length L of the animal.

The values H_(P), W_(P), and L provide an approximate, 3-dimensionalgeometric measurement (width, height, length) of the skeletal size ofthe animal. The skeletal measurements H_(P), W_(P), and L are veryreflective of an individual animal's body tissue carrying capacity andgrowth potential, which can be useful in managing the cattle and inestimating the animal's skeletal size and rate of growth. An animal'sskeletal trunk length L is a better indicator of bone growth and is abetter predictor of mature body weight than shoulder or hip height,because animal skeletal growth is greater longitudinally thanvertically. Using known mathematical techniques or equations in the art,a skeletal coefficient for the animal can then be calculated using theskeletal dimensions of the animal. When the age of the animal is known,a frame score may be selected for future reference and assessment. As isknown, skeletal size collected over time and/or frame score areparameters that can be used to describe an animal's growth potential.Typically, an animal's frame score changes very little as the animalmatures. If age of the animal is approximated, measurements can beobtained throughout a feeding program to assign a frame score to theanimal. A number of measurements may be required in younger animals toestimate their frame score. Because the determination of a frame scorefor an animal is dependent upon the height, age, and sex of the animal,a parameter of skeletal size or a coefficient of the skeletal growthrate of the animal may be used instead of frame score to differentiatethe uniqueness of the animals.

The processing system 80 in FIGS. 1-2B can record and display data andresults of calculations in a number of different manners. In oneembodiment, for example, the processing system 80 can include a displayor printer that provides a read out of the stored, measured, andcalculated data. It is preferred that the processing system 80 includesoftware for calculating various aspects of the animal, such as framescore, skeletal coefficient, hip height, hip width, skeletal trunklength L, percent body fat and/or protein, etc. In addition, it ispreferred that the processing system 80 store relevant data relating tovariables used in the calculations, such as age, sex, breed, etc.

When an initial measurement for a specific animal identified visually orelectronically is obtained with unknown age, the body skeletal size canbe recorded by the disclosed system 10 and can be used as an initialreference for changes in size and weight of the animal obtained insubsequent measurements with the disclosed system 10. The subsequentmeasurement are preferably used to more accurately determine the ratesof skeletal and body tissue growth, which can be used to determine amore accurate frame score or eventual live animal mature size. Therepeated measurements provide predictable projections of animal skeletalgrowth rate for live animals (% bone, muscle, and fat) and eventualcarcass end-point or quality measurements (% bone, muscle, and fat).

A person skilled in the art will appreciate, however, that the bodycondition or empty body weight fat of cattle can vary between animalswith the same skeletal structure. Scoring cattle based on body condition(i.e., the body condition scoring (BCS) system) is an effectivemanagement tool used in the art. Problems associated with body conditioncan surface in several ways, such as parasite and diseasesusceptibility, carcass quality grade, etc. Carcass quality grade orspecification, which is correlated to the body condition of the animal,represents the economic value of an animal's carcass based on thepercentage of bone, muscle, and fat. Management decisions involving thenutrition of the cattle are important to achieve the best animal bodycondition and carcass quality grade. Therefore, using body conditionscoring (BCS) with the disclosed system 10 can aid in nutritionmanagement of the cattle. In this way, the disclosed system can be usedto assess live cattle tissue composition and project how many days onfeed are required (dependent upon energy density of the rations) tobring the cattle to a specific live tissue composition for eventualmarketing of the animal's carcass.

As is known in the art, body condition scores describe the degree of“fatness” of a cow in a numerical range of 1 to 9, with 1 being verythin, 9 being excessively fat, and 5 being average. To use the BCSsystem effectively, an operator must understand which areas of the cowanatomy deposit fat and must account for a number of factors, such aspregnancy status, gut fill, hair coat, age, etc. Live weight of thecattle is not the determining factor for body condition and fatreserves. Animals can have different live weights but similar bodycondition scores. Likewise, animals of similar live weight may differ inbody condition. Using the North American Cow Body Condition Scoring(BCS) system, for example, a “thin” cow weighing about 383-kg may have aframe score of 4 and a pelvic height of 1.27-m. This “thin” cow may havea BCS of 3, corresponding to about 11.3% empty body weight fat or 12.6%carcass fat. In contrast, a “fat” cow weighing about 522-kg may have thesame frame score of 4 and the same pelvic height of 1.27-m. This “fat”cow may have a BCS of 7, corresponding to about 26.4% empty body weightfat or 29.1% carcass fat. In other words, the difference of 139-kg or15.1% empty body weight fat is dependent upon total empty body weightfat of the cow and is independent of skeletal structure.

With the understanding that the body condition or empty body weight fatof cattle can vary between animals with the same skeletal structure, itis preferred that the measurement of the skeletal structure obtainedwith the disclosed system be interpreted with additional information ofthe cattle. Accordingly, a person skilled in the art will appreciatethat the values H_(P), W_(P), and L obtained with the disclosed systemalong with the weight, age, breed, sex, and other physicalcharacteristics of the cattle can be interpreted using a number oftechniques known in the art. For example, the NRC Beef 1996 Model, theCornell Model, Body Condition Scoring, and a number of other techniquesbased on various measurements of the animal are known in the art and canbe used by the disclosed system.

Using measurements obtained from the disclosed system along withadditional information from techniques known in the art, the disclosedsystem can further enable feedlot managers to manage, sort, and monitoranimals. In one example, the percentage of body fat of the animal can becalculated from the skeletal size of the animal and their known weight.Establishing percentage of empty body weight due to body fat on theanimal can then help in accessing health risks to the animal caused bystressful environments. For example, the empty body weight related tobody fat indicates the physiological condition of the animal and theirrisk to central nervous distress (hormonal changes e.g. diabetes &hypothalamus control).

Knowing the frame score, growth potential, and other determiningcharacteristics of the animal obtained with the disclosed systemcombined with techniques known in the art enables animal managers toalso advantageously make a number of predictive assessments anddecisions about the animals. In one example, determining characteristicsof the animal obtained with the disclosed system can be used for feedingand sorting the animals. For example, growth potential of the animal canbe used to predict an animal's rate of growth, days on feed, or energyrequirements throughout the finishing period. By determining the growthrate of an animal through predictive equations, an appropriate feedingprogram to achieve eventual live animal tissue composition or carcassend-point (% bone, muscle, and fat) can also be calculated.

In another example, knowing the determining characteristics of theanimal can help animal managers to allocate feed resources and toclassify and sort animals into specific groups. These results couldincrease the value of the animals, reduce the cost of production, orboth. For example, the required amount of feed energy to produce adesired weight gain with a specific percentage of live animal empty bodyweight fat or carcass percentage fat may be projected throughcalculations using models known in the art. It is further believed thatusing skeletal measurements obtained with the disclosed system andmethod, for example, can improve feeding management of cattle withcompensatory gain or with “shrink”—the decrease in body weight due towater loss.

In yet another example, the determining characteristics, such as thegrowth potential of the animal, obtained with the disclosed system 10can be used to determine the best application of growth promotants, suchas the types and quantities of growth promotants or feed additivere-partitioning agents desired. Implants of hormone growth promotant(HGP), which are combinations of estrogenic and androgenic compounds,are used in the beef industry to increase bone and protein deposition,which subsequently suppresses fat deposition. Cattle are commonlytreated with an implant HGP to increase bone and muscle deposition. Acombination of implant HGPs may be used on an individual animalthroughout its life. By assessing the skeletal growth rate for an animalwith the disclosed system and method, an animal manager can select aspecific implant HGP or combination of implant HGPs to achieve a desiredtissue composition of the animal. The feed additive re-partitioningagents, such as beta-agonist, have an anabolic and carcassre-partitioning effect concomitant to the influence of an HGP. The feedadditive re-partitioning agents act primarily to increase body protein(mainly skeletal muscle) and to decrease fat content. Within a feedingprogram, time period for accurately selecting the use of these productsis dependent upon animal's growth potential, empty body weight fat, andeventual desired animal slaughter chemical end point. In a furtherexample, knowing the body sizes of animals can be used to accuratelystock the animals in defined housing spaces of a feedlot, such ashousing pens, boat pens, outside pens, and transport trailers.Furthermore, determining characteristics obtained with the disclosedsystem 10 may also be used to select animals suitable for breedingpurposes. For example, repeated skeletal measurements of the animalsover time can help to select heifers and bulls for breeding purposes.

It will be appreciated that aspects of the disclosed system and methodof the present disclosure can be used on animals other than cattle, suchas pigs and even humans. The disclosed system and method could bemodified for the monitoring of the optimum growth of the following farmanimals: replacement dairy heifers, bulls, sheep, goats, and horses. Forexample, the rate of growth of dairy heifers could be significant inmammary gland development and other desirable characteristics. Earlyskeletal features of bulls and racehorses, for example, could besignificant in the prediction of mature structural conformation, whichare very important features in the performance of these animals.

Not only can the disclosed system and method be used to determinephysical dimensions of an animal, but also the disclosed system andmethod can be used to position animals based on measurements made. Forexample, the disclosed system and method can be used to center a beef orswine carcass for automated splitting of the carcass in a meatpackinghouse. In addition, by making a determination of the leg positions andthe pelvic height and width, for example, the disclosed system andmethod can be used to select an area on an animal for applying medicalproducts, such as anthelmintics and tick or fly control, or to select anarea on the animal for placing an ultrasound transducer to determinesubcutaneous rib fat.

The foregoing description of preferred and other embodiments is notintended to limit or restrict the scope or applicability of theinventive concepts that were conceived of by the Applicant. In exchangefor disclosing the inventive concepts contained herein, the Applicantdesires all patent rights afforded by the appended claims. Therefore, itis intended that the invention include all modifications and alterationsto the full extent that they come within the scope of the followingclaims or the equivalents thereof.

1. A method of measuring an animal having legs, comprising the steps of:obtaining an image of at least a portion of one or more legs of theanimal; and determining at least one physical dimension of the animalfrom the image.
 2. The method of claim 1, wherein the step of obtainingthe image of the portion of the one or more legs of the animal comprisesthe step of at least partially backlighting the one or more legs of theanimal.
 3. The method of claim 1, wherein the step of obtaining theimage comprises the step of capturing one or more silhouettes of theportion of the one or more legs of the animal.
 4. A method of measuringan animal comprising: backlighting a first portion of the animal,wherein the first portion includes at least a portion of a lower leg ofthe animal; determining an approximate standing height of a secondportion of the animal; and obtaining an image that includes a silhouetteof the first portion of the animal.
 5. The method of claim 4 furthercomprising positioning the animal within a housing unit.
 6. The methodof claim 5 further comprising mounting an optical device on the housingunit, wherein the optical device obtains the image that includes thesilhouette of the first portion of the animal.
 7. The method of claim 5further comprising mounting a light source on the housing unit.
 8. Themethod of claim 4 further comprising determining an approximate distancebetween at least one pair of legs of the animal.
 9. The method of claim4 further comprising determining an approximate width of at least oneleg of the animal.
 10. The method of claim 4 further comprisingdetermining an approximate skeletal trunk length of the animal.
 11. Themethod of claim 4 further comprising determining a first midpointbetween a first pair of legs, determining a second midpoint between asecond pair of legs, and determining an approximate distance between thefirst midpoint and the second midpoint.
 12. The method of claim 11further comprising scaling the approximate distance between the firstmidpoint and the second midpoint to approximate an approximate skeletallength of the animal.
 13. The method of claim 4 further comprisingmeasuring an approximate distance from an ultrasound transducer to thesecond portion of the animal to determine the approximate standingheight.
 14. The method of claim 4 further comprising determining anapproximate width of a third portion of the animal.
 15. The method ofclaim 14 further comprising measuring approximate distances from a pairof substantially opposing transducers to determine the approximate widthof the third portion of the animal.
 16. The method of claim 4 furthercomprising selecting an area on the animal to apply a medical product.17. The method of claim 4 further comprising determining subcutaneousfat of the animal with an ultrasound transducer.
 18. The method of claim4 further comprising analyzing the image with a processor.
 19. A methodof measuring an animal comprising: backlighting an animal, wherein atleast a lower portion of a leg of the animal is backlit; obtaining animage of the silhouette of the animal, wherein at least the silhouetteof the lower portion of the leg of the animal is obtained; anddetermining at least one physical dimension of the animal from theimage.
 20. The method of claim 19 wherein the at least one physicaldimension is a width of a leg, a separation between a pair of legs, askeletal trunk length of the animal, a pelvic height of the animal, apelvic width of the animal, a center of the animal, or a volume of theanimal.